Construction techniques for bored piling in sand using polymer fluids

Lam, Carlos; Jefferis, Stephan A.; Suckling, Tony

doi:10.1680/geng.13.00128

Cited by 14 publications

(5 citation statements)

References 6 publications

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“…Polymer fluids have been found to offer many benefits such as smaller site footprint, ease of fluid mixing, and better concrete-sand interface resistance (Lennon et al 2006;Lam et al 2014a). However, since polymer fluids are very different from their bentonite counterparts both physically and chemically, their methods of use are also very different (Jefferis and Lam 2013;Lam et al 2014b) and workmanship issues have arisen on some projects in the past (Berkovitz and Long 1995;Institution of Civil Engineers 2007). Therefore, despite the potential benefits many practicing engineers still remain wary of polymer use (Wheeler 2003).…”

Section: Introductionmentioning

confidence: 99%

Performance of Bored Piles Constructed Using Polymer Fluids: Lessons from European Experience

Lam

Jefferis

2016

J. Perform. Constr. Facil.

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Solutions of synthetic water-soluble polymers have been used for the construction of bored piles (drilled shafts) since the early 1990s. These engineered fluids are very different from conventional bentonite slurries but there is currently a serious lack of industry guidance. Despite their advantages over bentonite, performance issues have arisen in the past and foundation engineers remain wary of their use. To help practicing engineers avoid past pitfalls and to promote best practice, this paper presents a critical reappraisal of selected European case histories of bored piles constructed using polymer fluids. A collective reassessment is necessary in order to provide an overall picture of the situation as individual cases may show conflicting results. It is found that the completed piles can have excellent load-movement characteristics if polymer behavior is understood and respected. Conversely, excavation instability, structural defects, and poor pile performance can result if the special properties of these fluids are not fully appreciated and as a result they are not properly maintained. The findings presented in this paper will be useful for consultants and contractors when designing and constructing piles and diaphragm walls utilizing polymer fluids in the future.

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Section: Introductionmentioning

confidence: 99%

Performance of Bored Piles Constructed Using Polymer Fluids: Lessons from European Experience

Lam

Jefferis

2016

J. Perform. Constr. Facil.

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“…These findings were verified by Lam et al [ 9 ] and Lam [ 10 ], who observed that piles formed with polymer fluid significantly outperformed piles supported by bentonite fluid, and little difference was found between piles drilled within 7.5 h and 26 h. Bustamante et al [ 11 ] investigated piles constructed with polymer fluid in pyroclastic soil consisting of pumice and lapilli, and they concluded that polymer fluid showed no adverse effect on pile shaft resistance in the pyroclastic soils. Similar successful cases of polymer fluids as a pile bore stabilizer can also be found in sand [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 72%

Design and Evaluation of a Polymer Support Fluid in a Soil–Rock Mixture

Ying

Xia

et al. 2022

Polymers

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Soil–rock mixtures are commonly encountered in the construction of bored piles. Conventional bentonite support fluids have disadvantages, such as more significant environmental impacts, more complex mixing, bigger site footprint, weaker foundation performance, and overall low economies. The present study conducted a comprehensive investigation of partially hydrolyzed polyacrylamide (PHPA) polymer fluids, an alternative to bentonite ones, to drill into a soil-limestone mixture. The fluid flow pattern, aging behavior, and the influence of finer silty clay on polymer fluid were explored. The test results showed that polymer fluids were reasonably well fitted to the power-law model and were a good alternative to the conventional bentonite ones. In terms of their aging behavior, the remaining active viscosity of the polymer was at least 70% after a prolonged aging time of up to 30 days, showing the effective on-site use of polymer fluids. The mixing of silty clay significantly reduced the apparent viscosity of polymer fluids, with 10% silty clay causing a viscosity reduction of 76%, indicating the importance of fluid control in drilling these materials. A polymer formula, water + 0.08%PHPA + 0.1~0.5%Na2CO3, was proposed and was verified by drilling into a soil–limestone mixture. The polymer fluids led to small radial displacements around the boreholes with a high drilling quality. This work would be helpful for consultants and contractors designing and constructing bored piles in soil and rock mixtures utilizing polymer fluids.

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“…The fluid flow rate is dependent on PSF shear viscosity [35]. Because soil particles settling velocity in fluid depends on viscosity and elasticity, therefore, reasonable amount of detritus accumulation takes place at the basal part of excavation or at the upper (top) part of fresh concretion as it is termied into the hole [36][37]. Sedimentation of soil particles occurs in creeping flow regime (Reynolds number, R < 1) without influencing by fluid elasticity in agreeing with [38] who also reported no effect of fluid elasticity on the particle drag when Deborah number (De) < 0.1.…”

Section: Rheological Characteristics Of Phpas Polymer Support Fluids ...mentioning

confidence: 99%

Bentonite and polymeric support fluids used for stabilization in excavations

Akhtar

2023

Turkish Journal of Engineering

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Bentonite is a natural and finite mineral resource. Dilute suspensions of sodium montmorillonite clay in water represents bentonite slurries. Suspension and orientation of colloidal clay particles define rheological properties in bentonite slurry (BS). The BS has been used about seventy years to temporarily support the excavations. More recently, polymer support fluids (PSF) gained much popularity and are widely used compared to bentonite support fluids. The PSF are categorized into natural (pure) and synthetic polymers. Physico-chemical properties of PSF are different than BS irrespective of the quite similarity in the mode of action. Synthetic polymer fluids are molecularly engineered fluids that can be a popular alternative of conventional BS deployed as excavation support fluids in different foundation applications such as diaphragm wall panels and pile bores. The synthetically engineered fluids of polymers (water-soluble) are different from conventional BS. The PSF offer additional benefits because their use is cost effective, eco-friendly, and these polymers need smaller site footprint as well as easy preparation, mixing, handling, management and ultimately the final disposal. Nevertheless, synthetic polymers have advantage over bentonite, however, foundation engineers and scientists have also certain concerns about their use because of their performance related issues. For an efficient use of polymers, specific properties and in situ behavior of polymers as well as their sorption onto the soils must be recognized because the polymer concentration in the solution is decreased with time during their use. The present manuscript reviewed the relative performance of excavation support fluids and displayed an arranged marriage of physicochemical and rhelogical properties of natural and synthetic excavation support fluids used in the foundation industry. This information will be highly useful to scientific community for their future ventures and will lay a foundation to understand the mechanisms of stabilization in open and deep excavations.

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Construction techniques for bored piling in sand using polymer fluids

Cited by 14 publications

References 6 publications

Performance of Bored Piles Constructed Using Polymer Fluids: Lessons from European Experience

Performance of Bored Piles Constructed Using Polymer Fluids: Lessons from European Experience

Design and Evaluation of a Polymer Support Fluid in a Soil–Rock Mixture

Bentonite and polymeric support fluids used for stabilization in excavations

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